the formation constants (log k), of the complexes formed between a number of amino acids(glycine , l-valine and l-alanine) with p-sulfonatocalix [4] arene at varying temperatures (25± 0.1to 65 ± 0.1 °c) in aqueous solutions and at natural ph of p-sulphonato-calix [4] arene (ph=3.2) bymeans of uv-vis spectrophotometeric technique have been investigated. at this ph the guestmolecule is in its cat...

Lynch, Judith L. (Northwestern University, Evanston, Ill.), and Francis C. Neuhaus. On the mechanism of action of the antibiotic O-carbamyl-d-serine in Streptococcus faecalis. J. Bacteriol. 91:449-460. 1966.-The antibiotic O-carbamyl-d-serine, an analogue of d-alanine, is an inhibitor of bacterial cell-wall biosynthesis. Growth of Streptococcus faecalis R in the presence of O-carbamyl-d-serine ...

Isolated membrane vesicles from Escherichia coli B grown on DL-alanine-glycerol carry out amino acid active transport coupled to D-alanine oxidation by a membrane-bound dehydrogenase. Several other D-amino acids are substrates for this D-alanine dehydrogenase and also drive concentrative uptake of solutes. Additionally, L-alanine and L-serine can energize solute transport by virtue of conversio...

1. Lactation is associated with an increase in the arterial blood concentration of L-alanine and L-glutamate, but a decrease in that of L-glutamine compared with the corresponding values for virgin rats. 2. Virgin rats fed a 'cafeteria diet' that induces hyperphagia have increased arterial concentrations of L-alanine, L-glutamate and L-glutamine. During lactation L-alanine and L-glutamate conce...

The transport of L-alanine was studied using membrane vesicles derived from the brush borders of the rabbit renal proximal tubule. Preincubation of the renal membranes with L-alanine, but not D-alanine, accelerated exchange diffusion of L-alanine, i.e. stereospecific counter transport. The equilibrium uptake of L-alanine decreased with increasing medium osmolarity. Extrapolation to infinite med...

The presence of two kinds of l-amino acid dehydrogenase in resting spores of Bacillus subtilis was indicated. One of them was l-alanine dehydrogenase, which used only l-alanine as a substrate, and the other was nonspecific dehydrogenase, which used l-valine, l-isoleucine, l-leucine, and l-alanine (slightly) as substrates. Several properties of these dehydrogenases were compared.

The pH dependence of transport of the neutral amino acids L-serine and L-alanine by membrane vesicles of Streptococcus cremoris have been studied in detail. The rates of four modes of facilitated diffusion (e.g., influx, efflux, exchange, and counterflow) of L-serine and L-alanine increase with increasing H+ concentration. Rates of artificially imposed electrical potential across the membrane (...

At least two transport systems serve for the entry of alanine, glycine, and serine into Escherichia coli. One of these systems serves mainly for glycine, d-alanine, and d-serine and to some extent for l-alanine, whereas the second serves for l-alanine and perhaps l-serine. These two transport systems have been characterized by kinetic studies and by inhibition analysis. Reciprocal plots for l-a...